Root tear of the meniscus: biomechanical evaluation of an arthroscopic refixation technique.

BACKGROUND: Aim of the current study was to evaluate the structural properties of an arthroscopic refixation technique for meniscal root tears. HYPOTHESIS: Arthroscopic two suture root tear refixation technique using a transtibial approach restores the structural properties of the intact meniscus attachment more closely than a one suture technique. METHODS: Lateral root tear refixation was performed in a porcine knee model. Using a material testing machine, structural properties were determined after a cyclic loading protocol comparing transtibial tunnel reconstruction using one or a double suture technique. Intact posterior horn served as control group. RESULTS: Elongation after cyclic testing was significantly lower for intact and two suture technique when compared to single suture technique. Stiffness was significantly higher for intact constructs with a mean of 53.7 (±6.5) N/m and two suture technique with 44.8 (±9.9) N/m when compared to one suture technique with a mean of 37.1 (±5.4) N/m. In elongation and stiffness, no differences were found between intact and two suture technique. Ultimate failure loads were 325.6 (±77) N for the intact, 273.6 (±45.6) N for two suture technique and 149.8 (±24.3) N for the one suture technique. Both reconstruction techniques showed significantly lower ultimate failure load when compared to the intact control. CONCLUSION: Structural properties of root tear fixation using a transtibial single suture technique showed significantly higher elongation and lower stiffness and failure load after cyclic loading compared to the intact, whereas a two suture technique showed no difference in elongation and stiffness; however, lower failure load.

Structural properties of a new fixation strategy in double bundle ACL reconstruction: the MiniShim.

INTRODUCTION: Double-bundle reconstruction of the ACL has become the focus of scientific and clinical interest in the last years. However, there is still a discussion about the most appropriate technique for graft fixation. Both, extracortical fixation systems like the Endobutton and aperture fixation by interference screws have advantages as well as disadvantages. Aim of this study was to analyze the biomechanical properties of a new small wedge shaped implant (MiniShim, Karl Storz, Germany) for the fixation of a soft tissue graft in double bundle ACL reconstruction and to compare it to an aperture fixation by interference screw and an extracortical fixation. METHODS: Porcine knees and flexor tendons were used for this study. 5 and 6 mm tunnels were drilled. The following fixation strategies were tested: 4 and 5 mm MiniShim (Karl Storz Germany), 6 mm interference screw (MegaFix, Karl Storz, Germany), hybridfixation by FlippTack (FlippTack, Karl Storz, Germany) and MiniShim and hybridfixation by FlippTack and 6 mm interference screw. All fixation strategies were tested with a 5 and 6 mm tendon graft. Maximum load, yield load and stiffness were recorded using a material testing machine. Load was applied in line with the bone tunnel. Grafts were cyclically preconditioned between 0 and 20 N for 10 cycles before the graft-bone-complex was loaded to failure. Statistical evaluation was performed using SPSS Version 11.0. RESULTS: Load to failure for the 5 mm graft was 81.1 and 118.0 N for the 4 and 5 mm MiniShims. Fixation by interference screw reached 237.4 N. The extracortical fixation resulted in a load to failure of 471.7 N. Load to failure for the 6 mm tendon grafts was 52.0 and 92.8 N for the 4 and 5 mm MiniShims. Fixation by interference screw resulted in a load to failure of 214.0 N. Extracortical fixation failed at 451.7 N. The difference between MiniShim and interference screw was statistically significant. Load to failure was significantly higher for extracortical fixation compared to fixation by MiniShim or interference screw. Hybrid fixation showed higher fixation strength compared to fixation by interference screw or MiniShim alone. This difference was statistically significant. Stiffness was significantly higher for fixation by interference screw compared to extracortical fixation and fixation by MiniShim. Four different modes of failure could be seen. All 4 mm MiniShims failed by slippage of the tendon past the MiniShim. In the 5 mm group the fixation failed by pullout of the MiniShim or the tendon past the MiniShim. Hybrid fixation failed by rupture of the linkage material. When the graft was fixed by an interference screw failure occurred by rupture of the tendon at the fixation side. CONCLUSION: Hybrid fixation using the MiniShim provides biomechanical properties strong enough to withstand the forces occurring during rehabilitation and comparable to the fixation strength provided by interference screw. While fixation by MiniShim alone does not provide sufficient fixation strength in double bundle ACL reconstruction, hybridfixation using a cortical fixation by FlippTack is an alternative to aperture fixation by interference screw concerning primary stability.

Structural properties of a new device for graft fixation in cruciate ligament reconstruction: the shim technique.

INTRODUCTION: In ACL reconstruction using a soft tissue graft, aperture fixation with interference screws (IFS) can lacerate and rotate the graft and cause primary tunnel widening. To overcome these downsides, a new wedge-shaped implant (MegaShim, Karl Storz, Germany) was developed. We hypothesized that aperture fixation of hamstring ACL reconstruction using the MegaShim technique shows comparable structural properties when compared to interference screw fixation. METHODS: In a porcine knee model, ACL reconstructions with a tunnel diameter of 6, 7, 8 and 9 mm were performed and human hamstring grafts were fixed using the MegaShim technique (group I). In group 2, grafts were fixed in a hybrid fixation using a MegaShim and cortical flip button (FlippTack, Karl Storz, Germany). Interference screw graft fixation served as a control group (group III). Maximum load, yield load and stiffness were recorded using material testing machine. Grafts were cyclically preconditioned between 0 and 20 N for 10 cycles before the graft-bone complex was loaded to failure. Statistical evaluation was performed using SPSS Version 11.0. RESULTS: Mean maximum load to failure for the hybrid fixation was significantly higher than after interference screw or MegaShim fixation. The difference between MegaShim and interference screw fixation showed no significant difference for 6 and 7 mm sizes. An 8 and 9 mm MegaShim fixation resulted in significantly lower ultimate failure load compared to interference screw fixation. Stiffness of grafts fixed using 6 mm MegaShim was significantly lower than grafts fixed with hybrid or interference screw fixation, whereas no significant differences were found in the 7, 8, and 9 mm fixations. CONCLUSION: Aperture fixation using the MegaShim technique provides comparable structural properties compared to interference screw fixation. Hybrid fixation using MegaShim and cortical flip button results in significantly higher ultimate failure loads than both aperture fixation approaches. Smaller grafts (6 mm) showed significantly lower ultimate failure load and stiffness than interference screw fixation. The "MegaShim technique" is an alternative to interference screw fixation concerning initial fixation strength.

[Fracture of the tibial head]. / Tibiakopffraktur.

Fractures of the tibial head are marked by huge variety. They can be classified into fractures of the tibial plateau, luxation fractures, and comminuted fractures. Luxation fractures are commonly associated with lesions of the menisci and intra- and extra-articular ligaments. Several factors may be responsible for the development of post-traumatic OA: anatomically nonreduced joint surface, malalignment, and unaddressed associated injuries. Therefore a sophisticated therapeutic regime is necessary. In case of severely damaged soft tissue or unstable patients, the fracture should first be reduced and fixed with an external fixateur and the osteosynthesis should be performed in a second setting. Arthroscopically assisted reduction and osteosynthesis are indicated for fractures of the tibial eminence, crack fractures, and impression fractures. Comminuted fractures can be addressed via several different incisions. Due to locking plates, the bilateral use of large plates can be avoided. In specific cases such as compound fractures and for patients with low compliance, hybrid fixateurs may be an alternative.

Little league shoulder syndrome in an adolescent cricket player.

The first case of little league shoulder syndrome in a cricket player is reported. The condition has been reported in baseball pitchers and is characterised by a proximal humeral epiphyseolysis.

[Epidemiology of injuries in juvenile handball players]. / Epidemiologie von Handballverletzungen im Jugendalter.

INTRODUCTION: Aim of the study was to elucidate epidemiological aspects and injury mechanisms in juvenile team handball. METHOD: A standardized questionnaire was used to evaluate the injuries of 100 juvenile players (50 male, 50 female, year of birth 1982/83). RESULTS: A total of 130 injuries were recorded of 73 players. Most of the injuries (73.1%) occurred between the age of 15 and 18. Approximately two thirds of the injuries (69.2%) occurred in a competition and most of them in an offensive situation. Backcourt players (29.0%), line players (27.5%), and goalkeepers (17.0%.) were the player positions to be most injured. Female goalkeepers were three times more often injured than male ones at the same age. Most injuries applied to the foot and the ankle (32.0%), followed by the finger joint (26.9%) and the knee (24.6%). The most frequent ankle injuries were ruptures of the lateral ankle ligaments. The knee joint was affected by the most severe injuries with the need of surgical therapy. The most common injury concerning the knee joint was rupture of the anterior cruciate ligament (ACL). Eleven ACL tears were recorded in the age between 15 and 18 years (12-14 years: 1; 8-12 years: 0). The most typical game situation at the point of injury was catching a ball (38.5%), contact situation with the opponent (34.5%), or landing after a jump (26.2%). CONCLUSIONS: This study allows conclusions concerning prevention of injuries in juvenile team handball. There is apparently a difference in muscle strength and coordination of the youth handball player, especially at the age of 15-18 years, which has to be addressed. Therefore the authors recommend a proprioceptive training program as well as exercises to improve jumping techniques. Special strengthening training for the finger muscles might help to prevent finger injuries. The frequency of contact injuries underlines the importance of a "fair play" campaign among young players.

[Mechanisms and prevention of windsurfing injuries]. / Verletzungen und Verletzungsmechanismen beim Windsurfen.

Aim of this study was to analyse the mechanisms of windsurfing injuries. For this purpose we performed a internet based survey among 327 windsurfers in Germany. Overall 630 accidents have been registered among all 327 athletes during the 2000 season. The majority of injuries were classified as minor injury. The most common injury was the bruise. 70 participants reported fractures, 26 participants ruptured a ligament. 280 injuries required medical treatment; in 67 cases even surgical treatment was necessary. The majority of accidents happened at wind power of 5-6 Beaufort after 2 hour exercise. A technical mistake was the most frequent cause for the accident. The most dangerous manoeuvres were difficult jumps (e. g. front loop, backward loop, 70 injuries). In 46 cases the weather conditions were underestimated. Only 10 windsurfers reported about broken material as cause for the injury. One half of the injuries happened in wave conditions. The analysis of injury mechanisms allows conclusions regarding injury prevention. A longer break after 60 minutes windsurfing might help to prevent injuries due to poor physical fitness. After one hour windsurfing without a break training of difficult manoeuvres should not be performed. The use of a helmet might prevent head injuries during training of difficult jumps. "Overpower situations" should be prevented by choosing the right board and sail size.

[Prevention of lower extremity injuries in handball: initial results of the handball injuries prevention programme]. / Prävention von Verletzungen der unteren Extremität im Handball: Erste Ergebnisse des Kieler Handball-Verletzungs-Präventionsprogrammes.

INTRODUCTION: Injuries of the lower extremity lead to disability to perform sports and may cause degenerative changes of the joints. Hence, we developed a specific injury prevention programme for European team handball and tested this programme in a prospective study. METHOD: One handball team (2 nd division) performed a proprioceptive and neuromuscular training during the preseason. The programme consists of 3 different components: 1. Information on injury mechanisms, 2. Proprioceptive training, and 3. Jump training. During the season the exercises have been continued with lower intensity. Another handball team which performed no injury prevention training served as control. Injuries were recorded in a prospective manner. In a retrospective arm of the study we compared the frequency of severe injuries of the training season with the frequency of severe injuries during the last season. RESULTS: In comparison to the last year no player from the prevention training team suffered a severe injury of the ankle or the knee. During the last season three athletes ruptured their anterior cruciate ligament. In the untrained control group one athlete suffered from an ACL rupture and one athlete had a rupture of the lateral ankle ligaments. These findings have no statistical significance because of the low number of individuals investigated. However, the incidence of light and medium injuries was significantly lower in the injury prevention group. CONCLUSIONS: This study demonstrates that proprioceptive and neuromuscular training is appropriate for the prevention of lower extremity injuries. Prevention strategies should be included in routine handball training programmes.

[Biomechanical examinations of the efficacy of wrist guards in inline skating]. / Biomechanische Untersuchungen zur Effektivität von Handgelenksprotektoren für das Inline-Skating.

INTRODUCTION: Fractures of the wrist and forearm are the most frequent injuries in Inline-Skating. Clinical experience has shown that these injuries can be prevented the use of wrist protectors. But various authors have shown that fractures can also occur despite the use of wrist protectors. Aim of this study was to examine different wrist protectors in a biomechanical set up. METHOD: A standardized trauma was simulated using an artificial hand with a certain weight. The forces with or without protective devices have been recorded by a force moment sensor. The results of different protectors have been compared. RESULTS: A mean force of 956 N was measured without the use of a protective device. With the application of a wrist protector these forces were reduced between 4 and 20 %. The best values have been reached with models with a strong base plate. CONCLUSIONS: The results of the present study may explain the clinical observation that wrist and forearm fractures can occur despite the use of a wrist guard. The protective effect of a wrist protector depends highly on the model that is used.

[Injuries in Olympic handball tournaments: a video analysis]. / Verletzungen im olympischen Handballturnier: eine Videoanalyse.

INTRODUCTION: The aim of the study was to achieve injury situations in European team handball with a video based method. METHODS: A video tape containing 59 injuries of an Olympic handball tournament were analyzed by two observers (sports-scientist, orthopaedic surgeon). The analysis was based on a method previously published by Teitz, which was developed to analyze ACL-injuries. The parameters body region, field position, contact/non-contact, offense/defense, field player/goal keeper were mainly used. RESULTS: The most injuries were localized at the head (N = 20), the lower limb (N = 15), thorax and abdomen (N = 9) and the upper limb (N = 9). Concerning the field, the most injuries were in the midfield (N = 20), followed by the left (N = 13) and right (N = 9) outside position. The injured players were mostly in the offense (84 %), and in the majority of cases the field players were affected (97 %). 86 % of the injuries accomplished by contact. CONCLUSION: The head has a high risk, predominantly of contact injury. Contact-injuries could only be reduced by strict decisions of the referees. Non-contact injuries should be prevented by a special coordinative training.

[Stage-adapted treatment of infection after reconstruction of the anterior cruciate ligament]. / Stadiengerechte Therapie bei Infekten nach Ersatzplastik des vorderen Kreuzbandes.

OBJECTIVE: Debridement and irrigation of the knee joint and the donor site to reduce the amount of bacteria and to remove bacterial enzymes and inflammatory cytokines in cases with infection after replacement of the anterior cruciate ligament (ACL). INDICATIONS: Proven infection, suspected infection. CONTRAINDICATIONS: High anesthesiological risk. SURGICAL TECHNIQUE: The therapy of infections after ACL reconstruction depends on the different stages as described by Gächter. In stage I and II, arthroscopic debridement and irrigation (about 10 l) of all compartments is performed. Several biopsies for microbiological analysis are obtained during surgery. Broad-spectrum antibiotic therapy started immediately after surgery. Once the resistance of the bacteria is known, antibiotic therapy may be changed according to the results. When pain, swelling, elevated CRP, or white blood cells persists, arthroscopic irrigation is repeated. In stage III, a complete arthroscopic synovectomy is performed. When the graft is intact, it is left in situ. Resection is performed in case of graft insufficiency, tunnel malplacement, or persistent infection. When the bone tunnels are affected, they should be debrided. In stage IV with osteolysis, an arthrotomy with open debridement may be required. The surgical therapy can be supported with the application of local antibiotics. REHABILITATION: Redon drainage is left in situ until the next irrigation is performed, control of wound and laboratory results, passive exercises, physiotherapy, systemic antibiotic therapy. RESULTS: Between 2008 and 2013, we treated 13 patients with an infection after replacement of the ACL. In all cases, complete healing was achieved. In 4 cases, the graft was resected. In 2 patients, arthrofibrosis developed and arthrolysis was required.

[Anatomic reconstruction of the anterior cruciate ligament in single bundle technique]. / Die anatomische Ersatzplastik des vorderen Kreuzbands in Einzelbündeltechnik.

OBJECTIVE: Restore the knee stability by ACL reconstruction of the anterior cruciate ligament. INDICATION: Acute and chronic functional instability with rupture of the anterior cruciate ligament giving way phenomena, acute rupture of the anterior cruciate ligament with concomitant meniscus repair. CONTRAINDICATIONS: Local infection in the knee joint, local soft tissue damage, lack of cooperation of the patient. SURGICAL TECHNIQUE: The operation begins with the examination under anesthesia. It follows an arthroscopic examination of the knee and the arthroscopic treatment of accompanying intra-articular lesions (meniscus and cartilage damage). The semitendinosus tendon is harvested via a 3 cm skin incision medial to the tibial tuberosity. A four stranded tendon graft is prepared with a minimum length of 6.5 cm. Alternative grafts for this technique are the patellar tendon, quadriceps tendon, and allografts. The femoral tunnel for the ACL graft is drilled via a deep anteromedial portal under arthroscopic control. For precise placement of the guide wire a specific offset aimer is used. For drilling the knee must be flexed more than 110°. Landmarks are the intercondylar line and the cartilage-bone interface. The position of the guide wire is always controlled by the medial portal (medial portal view). The guide wire is overdrilled with a cannulated drill (4.5 mm when a flip tack is used). The drill diameter for the 30 mm long blind tunnel is chosen according to the graft diameter. A gentle tunnel preparation may be achieved with the use of dilators. At the tibia, the anterior horn of the lateral meniscus is used as a landmark in the absence of ACL stump. The guide wire is first overdrilled with a 6 mm drill. Slight adjustments to the tibial tunnel location can be archieved when the guide wire is overdrilled eccentrically with a larger drill. At the femur an extracortical fixation technique with a flip button is preferred. At the tibia, a hybrid fixation with absorbable interference screw and button is used. REHABILITATION: The rehabilitation program is divided into three phases. During the inflammatory phase (1st-2nd week) control of pain and swelling is recommended. The patient is immobilized with 20 kg partial weight bearing. During the proliferative phase (3 nd-6th week), load and mobility are slowly increased. Goal of this phase is it full extension. Exercises should be performed in a closed chain. During the remodeling phase strength and coordination exercises can be started. Athletes should not return to competitive sports before the 6th to 8th month. RESULTS: In a prospective study, we have examined 21 patients treated with an anatomic anterior cruciate ligament reconstruction in single-bundle technique, after two years. As graft the semitendinosus was used. The postoperative MRI diagnosis showed that all tunnels were positioned anatomically. KT 1000 measurement showed that the difference of anterior translation decreased from an average of 6.4-1.7 mm. A sliding pivot shift phenomenon was detected in only one patient. The postoperative Lysholmscore was 94.2 points.

[Avulsion injury to the posterior horn of the lateral meniscus. Technique for arthroscopic refixation]. / Avulsionsverletzung des Aussenmeniskushinterhorns. Arthroskopische Refixationstechnik.

An avulsion of the posterior tibial insertion of the meniscus (root tear) is a rare clinical diagnosis. Yet, due to the inconsistent clinical symptoms and the difficult arthroscopic assessment, an injury to the root of the meniscus can be easily missed. We present a possible technique for arthroscopic management of root tears using a tibial tunnel approach. A possible injury mechanism could be a rotational distortion of the knee. Another mechanism of injury is an overly posterior tunnel placement in ACL reconstruction. The clinical assessment of the lesion is based on thorough arthroscopic diagnosis of the lateral posterior horn in the figure of 4 position. A tibial ACL aimer can be used to locate a K-wire in the anatomical footprint of the posterior root of the meniscus. After overdrilling using a 4.5-mm drill, two sutures can be passed through the meniscal tissue and the sutures can be pulled out of the tibial tunnel. Extracortical fixation can be used by tying the sutures over a button.A root tear of the meniscus is a difficult clinical and arthroscopic diagnosis. A possibility for refixation of this lesion is to use a tibial tunnel technique. An associated injury to the ACL facilitates the tunnel placement and the suture management.

[Fracture of the tibial head]. / Tibiakopffraktur.

Fractures of the tibial head are severe injuries, characterized by enormous variety. Fractures can be classified into fractures of the tibial plateau, luxation fractures, and comminuted fractures. Due to the mechanism of injury luxation fractures are frequently associated with lesions of the menisci and intra- and extra-articular ligaments. Multiple factors can be etiologic for post-traumatic gonarthrosis: nonanatomic reduction of the joint surface, malalignment, and unaddressed associated injuries. Therefore in addition to diagnostic steps such as X-ray, CT scan, and MRI a sophisticated therapeutic regime is necessary. In cases with severely damaged soft tissue or unstable patients, the fracture should initially be reduced and fixed with an external fixator and the definite fixation should be performed in a second setting. Arthroscopically assisted treatment is reserved for fractures of the tibial eminence, crack fractures, and impression fractures. Comminuted and bilateral fractures can be addressed via different incisions. New locking plates with angular stability allow avoidance of bilateral plating in most situations. In specific cases such as compound fractures and for patients with low compliance, a hybrid fixator may be a well-chosen alternative.

[Kitesurfing injuries. A trendy youth sport ]. / Verletzungen beim Kitesurfen. Eine junge Trendsportart.

The aim of this review article is to give an overview of current knowledge on kitesurfing injuries. As part of a prospective study, the overall self-reported injury rate was 7.0 per 1000 h of practice. One fatal accident and 11 severe injuries occurred. The most commonly injured sites were foot and ankle, head, chest, and knee. Contusions, abrasions, and lacerations were amongst the most frequent injuries. None of the athletes suffering a head injury used a helmet; the board had been flung against the head by the elastic board leech in all cases. The most common injury situation was the jump. Fifty-six percent of the injuries were attributed to the inability to detach the kite from the harness. There was a tendency that athletes using a quick release system, which enables the surfers to detach the kite in emergency situations, sustained fewer injuries than athletes without such a release system. In conclusion, kitesurfing is a sport with a comparably high injury rate. Preventive measures can reduce the injury rate considerably.

["Shrinkage of cruciate ligaments"--a biomechanical study. Shrinkage of elongated cruciate ligaments using an application of radiofrequency energy]. / 'Kreuzbandschrumpfung"--eine biomechanische Studie. Schrumpfung von elongierten Kreuzbändern unter Anwendung von Radiofrequenzenergie.

The aim of this study was to evaluate structural properties of native and elongated bovine anterior cruciate ligaments after the application of bipolar radiofrequency. Using a material testing machine typical load-elongation curves were used to determine the initial strength of untreated (group 1, n = 20) and elongated cruciate ligaments (group 2, n = 20) after treatment with bipolar radiofrequency (ArthroCare). After the application of a cyclic loading protocol (1000 x 400 N) elongation, yield load, maximal load, and stiffness were determined. Native ligaments served as a control group (group 3, n = 20). In both groups 4 mm reduction in length was caused by the application of radiofrequency. Elongation was significantly higher; yield load, maximal load, and stiffness of cruciate ligaments treated with radiofrequency (groups 1 and 2) were significantly reduced after the application of a cyclic loading protocol in comparison to the control group (p < 0.05). Group 2 ligaments showed the lowest values. The application of radiofrequency weakens the biomechanical properties of native and elongated cruciate ligaments significantly. When radiofrequency energy is used to shrink elongated cruciate ligaments, a nonaggressive rehabilitation protocol should be applied.